cho biết x và y là hai đại lượng tỉ lệ thuận x1 và x2 là hai giá trị khác nhau của x và và y1 y2 là hai giá trị tương ứng của y tính x1 x2 x3 biết x1=3y;2y1-x1=-7;x2=45

A=100^2-99^2+98^2-97^2+..........+2^2-1 B=(20^2+18^2+16^2+........+4^2+2)-19^2+17^2+15^2+.......3^2-1 C=(-1)^n.(-1)^2n+1.(-1)^n+1

cho a và b là hai số tự nhiên. giải thích tại sao nếu (a + b) ⋮ m và a ⋮ m thì b ⋮ m

TÍNH (3x^3-2x^2+x+2 ). (5x^2) b, (3x^2+5x-2). (2x^2-4x+3)

giúp e vớiiiiiii nhớ vẽ đồ thị đầy đủ căn cứ trên đồ thị nhá!!

Chia động từ ở thì tương lai đơn: I __________ (not /clean) this room. If it not rains, we ___________________ (go) to climb the mountain. I guess, he ________________ ( pass) the exam. My little boy ___________ (eat) the soup. ____________you__________( play) badminton next Sunday

Có bao nhiêu tinh trùng được tạo thành qua quá trình phát sinh giao tử từ 5 tế bào mầm sinh dục đực?

23. Would you like _______ a message ? (to leave , leave , leaving , left ) 24. Let’s ________ inside the center, at the cafe’ corner. ( met, meet, to meet, meeting) 25. Tom works in this big city but actually he _____ in a small country village. (born, was born, is born, has been born) 26. The post office is not far _______ my house. ( at, on, in, from ) 27. I’d like to speak _________ the manager, please. ( to, for , with, from ) 28. Hoa loves children. She ________ a teacher when she is old enough. ( is, is going to be, was, was going) 29. Tuan is going to invite twenty of his friends to his birthday party ____________________.

Cho tam giác ABC trên BC lấy trung điểm I Trên AI lấy điểm M sao cho AM =2/3 AI trên BM lấy điểm K sao cho BK =1/3BM.Tính a)SABI B)SABM C)SAKM biết Sa ABC=90cm2 mong mn giúp em ạ^^

23. Would you like _______ a message ? (to leave , leave , leaving , left ) 24. Let’s ________ inside the center, at the cafe’ corner. ( met, meet, to meet, meeting) 25. Tom works in this big city but actually he _____ in a small country village. (born, was born, is born, has been born) 26. The post office is not far _______ my house. ( at, on, in, from ) 27. I’d like to speak _________ the manager, please. ( to, for , with, from ) 28. Hoa loves children. She ________ a teacher when she is old enough. ( is, is going to be, was, was going) 29. Tuan is going to invite twenty of his friends to his birthday party ____________________.